Apparatus for determining the consistency of concrete mix



June 30, 1953 G. w. CRONK I 2,643,542

APPARATUS FOR DETERMINING THE CONSISTENCY OF CONCRETE MIX Filed Sept. 6, 1947 GEORGE w. CRONK INVENTOR.

Patented June 39, 1953 APPARATUS FOR DETERMINING THE CON= SISTENCY OF CONCRETE MIX George W. Cronk, East Orange, N. J., assignor to Worthington Corporation, a corporation of Delaware Application September 6, 1947, Serial No. 772,574

7 Claims.

This invention relates to concrete mixing equipment and, in particular, refers to a meter for indicating the consistency of materials being mixed in the drum.

As is well known in the art of concrete mixing, careful control must be maintained over the consistency or slump of the mix. It is the purpose of the present invention to provide visual means for indicating slump so that the operator may take the necessary measures to correct any undesirable variations therein. The invention is based on the principle that the power required to rotate the mixing drum varies as the consistency of the mix. Thus, variations in inlet pressure to a hydraulic motor that drives the drum are utilized to actuate a pressure gauge which the operator can observe to follow the mix ing conditions in the drum.

The present invention consists in a novel combination of known elements and is illustrated in the accompanying drawing which is a circuit diagram of a preferred arrangement of hydraulic units and their connection to a mixing drum.

In accordance with the art, the mixing drum i is rotatably mounted in any suitable manner on the frame of the concrete mixer (not shown). It has a gear 2 at its lower end by means of which it is rotated.

According to the present invention, the pinion 3 for the gear 2 is driven by a hydraulic motor 4. Pressure fluid is received by the motor 4 from the constant delivery pump 5 through the conduit ii. The conduits 1 and 8 connect the motor i and the pump 5, respectively, to the pressure fluid tank ii. A hand valve it in the line 6 provides manual means by which the operator can inhibit the flow of fluid to the motor A pressure gauge i i in the line ii visually indicates the pressure of the fluid supplied to the motor 4. A relief valve i2 in the line 6 is connected to the tank 9 by conduit it.

In operation, variations in the slump of the mix in drum i cause variations in the power required for rotation. Since the pump 5 delivers fluid at a constant rate, fluctuations in the load on motor i vary its resistance to the flow of fluid passing from line 6 to the tank 8 and therefore vary the pressure in line 5. Thus, an increase in power required for rotation, due to increased slump, increases the pressure in line 6. This is, of course, shown on the pressure gauge l l whereupon the operator can add water to the mix until the pressure gauge shows that the proper consistency has been obtained.

In case of excessive pressures in the circuit, the

valve [2 opens and the output of the pump 5 goes simply to the tank 9, thus preventing any possible dam-age.

When it is desired to stop rotation of the drum i, the operator shuts valve M. This blocks flow to the motor 4 and directs it through the relief valve i2 to the tank 9.

What is claimed is:

l. A slump meter for visually determining the consistency of the mixture in a mixing drum on mixing apparatus comprising, a hydraulically operated motor for rotating said mixing drum, a constant delivery pump for supplying pressure fluid to said motor, conduit means to carry said pressure fluid between said pump and said motor, and visual indicating means connected to said conduit means between said pump and said motor responsive to variations in the back pressure in said conduit caused by the variations in the consistency of the mixture in the mixing drum.

2. A slump meter for visually determining the consistency of the mixture in a mixing drum on mixing apparatus comprising, a hydraulically operated motor for rotating said mixing drum, a storage tank for hydraulic fluid, a constant delivery pump taking its suction from said tank for supplying said fluid under pressure to operate said motor, conduit means to carry said pressure fluid between said pump and said motor, return means for returning said fluid from said motor to said tank, and a visual indicating means connected to said conduit means between said pump and said motor responsive to variations in the back pressure in said conduit caused by the variation in the consistency of the mixture in the mixing drum.

3. A slump meter for visually determining the consistency of the mixture in a mixin drum on concrete mixing apparatus comprising, a hydraulically operated motor for rotating said mixing drum, a storage tank for hydraulic fluid, a constant delivery pump taking its suction from said tank, conduit means connecting the discharge side of said pump to the inlet side of said motor for supplying fluid under pressure to opcrate said motor, return means connected to the outlet side of said motor for returning said fluid to the tank, a visual indicating means connected to said conduit means between said pump and said motor responsive to variations in the back pressure in said conduit means caused by the variations in the consistency of the mixture in the mixing drum, means in said conduit means for controlling the flow of pressure fluid to said motor, and means for regulating the back pres- 3 sure in said conduit to a predetermined maximum.

4. In a slump meter as claimed in claim 3 wherein the means for controlling the pressure fluid to said motor includes a valve in said conduit means between the visual means and the motor.

5. In a slump meter as claimed in claim 3 wherein the means to regulate the back pressure includes a relief valve having its inlet side Icetween the said pump and the visual indicating means and its discharge side connected to said tank for returning fluid thereto.

6. A slump meter for visually determining the consistency of the mixture in a mixing drum on concrete mixing apparatus comprising, a hydraulically operated motor for rotating said mix ingdrum, a storage tank for hydraulic fluid, a constant delivery pump taking its suction from said tank, conduit means connecting the discharge side of said pump to the inlet side of said motor for supplying fluid under pressure to oper ate said motor, return means connected to the outlet side of said motor for returningsaid fluid to the tank, a visual indicating mean connected to said conduit means between said pump and said motor responsive to variations in the back pressure in said conduit means caused by the variations in the consistency of the mixture in the mixing drum, a valve in said conduit between said visual means and said motor to regulate the flow of pressure fluid to said motor, and a relief valve connected between said visual means and said pump on its inlet side and discharging into said tank from its discharge side for regulating the back pressure in said conduit to a predetermined maximum.

7. A slump meter for visually determining the consistency of the mixture in a mixing drum on concrete mixing equipment comprising, a storage tank for pressure fluid, a hydraulic motor for driving the mixing drum, said motor having an outlet connected to said tank, a pump having an inlet connected to said tank, conduit means for the passage of fluid under pressure from said pump to said motor, a pressure gauge in said conduit means, said pump being of the type which delivers fluid to said motor at a constant rate whereby variations in the load on the motor cor- V responding to variations in the slump will be refiected in variations in the back pressure in said conduit means and thus in the indications of said gage.

GEORGE W. CRONK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name v Date 1,449,458 Sutermeister Mar. 27, 1923 1,937,077 West Nov. 28, 1933 2,089,604 Hagy Aug. 10, 1937 2,354,634 Griswold July 25, 1944 2,361,460 Daugherty Oct. 31, 1944 2,440,614 -Postel Apr. 27, 1948 

